class A:
    def test(self):
        print('A test')

    def demo(self):
        print('A demo')


class B:
    def test(self):
        print('B test')

    def demo(self):
        print('B demo')


class C(A, B): # 多于多父类的类，调用顺序为 C A B
    def test(self):
        print('C test')


if __name__ == '__main__':
    c = C()
    c.test()
    print(C.__mro__)
    # 调用顺序：(<class '__main__.C'>, <class '__main__.A'>, <class '__main__.B'>, <class 'object'>)